High power lasers can inflict damage to an eye or a device if the light from the laser is intentionally or accidentally directed to an unprotected eye or device. As one example, airline and helicopter pilots have reported laser strikes where laser pointers are aimed at their cockpits. These laser strikes can cause a significant glare hazard through dazzle which makes it very difficult to see cockpit instrumentation or see outside the cockpit. Additionally, the laser might strike a pilot's eyes directly causing temporary or permanent blindness. As another example, a person may be working with a high power laser that has the potential to cause significant eye damage if the laser light is accidentally directed to their eyes or others present in the same proximity to the high power laser. As yet another example, a surveillance camera in a high security location may be accidently or intentionally disabled using a high power laser.
One prior approach to protect eyes from laser light is to employ absorbing substrates or lenses, typically based on dyes introduced into glass or plastic substrate material which are formulated to provide some blocking at one or more laser wavelengths through absorption. With this approach, a significant blocking from optical density (OD) of OD1 to OD7 or higher can be achieved at one or more laser wavelengths. The absorption of light does not depend on the angle of which the laser light is incident upon the substrate. However, the disadvantage of these dyes is that they are not particularly wavelength selective. Hence, absorbing lenses can undesirably block a significant portion of the visible spectrum resulting in a low luminance or photoptic transmittance through the lens. As well, there can be a poor colour discrimination in these absorbing substrates which can prohibit their use. In addition, the absorption material may break down after absorbing a high intensity of light; hence, the blocking may be substantially degraded and not provide the same laser blocking protection.
Thus, there is a need for eye protection glasses that provides good optical blocking at one or more specified laser wavelengths, good luminance transmittance and colour discrimination and a reduced reflection of ambient (or laser) light back into a user's eye off the backside of a lens. There is also a need for optical filters to protect devices such as surveillance cameras from being functionally impaired by high power lasers.